Reinterpretation of a remarkably well preserved pterosaur soft tissue from the Early Cretaceous of Brazil

ABSTRACT

The identification of some pterosaur bones and associated soft tissue from the Early Cretaceous of Brazil is a controversial issue. The specimen (DGM 1475-R) was previously mistaken as part of a forearm and the associated soft tissue was misinterpreted as part of the wing membrane near the radius and ulna. However, the bones described as the “radius and the ulna” are in fact the proximal part of a left humerus and a rib. The scapula, coracoid, and other ribs are also present. SEM analysis shows that there is no duplication of any layer (e.g., epidermis) and that structural fibers (except muscle fibers) are absent, contrary to what would be expected in a transverse section of wing membrane. This suggests that the soft tissue is part of the integument near the shoulder girdle and thorax, and is not part of the soft tissue primarily involved in flight (=wing membrane).